47 2 POPULAR SCIENCE MONTHLY 



must be taken by court and jury on his authority; it could not be 

 expected of the court, still less of the jury, that it should examine into 

 the soundness of the methods which he had employed. Yet it must be 

 p]ain from what has been pointed out above that, even assuming — 

 which is a great deal — the possibility of expending the necessary 

 amount of time and pains upon the inquiry, none but the most highly 

 qualified expert could be safely entrusted with it. Professor Munster- 

 berg is a man not only of the highest professional training, but of 

 extraordinary native powers of mind; yet he not only makes a funda- 

 mental error in one instance, but in a number of others overlooks ele- 

 ments essential to the true bearing of the facts upon the question in 

 hand. In addition to the points already noted, one other may be men- 

 tioned which throws perhaps an even stronger light on the pitfalls that 

 lie on all sides. It is a curious circumstance that in none of the 

 questions put by Professor Miinsterberg to his class does he give any 

 room (or at least any encouragement) to the simple answer, "I don't 

 know." How many of the queer guesses he got in response to the 

 question as to what caused the sound he made by striking the hidden 

 tuning-fork would have been choked off by the simple and straight- 

 forward plan of telling the students to answer only in case they felt 

 a reasonable assurance, there is no means of telling. And yet in court 

 a truthful witness would do that very thing. If he had heard a sound 

 the character of which he could not identify, he would so state to the 

 court, and not say it was a bell or a church organ or a human song 

 or what not. A man who, upon being asked to make the best guess 

 he can, makes a very bad guess is not necessarily an unreliable witness ; 

 lie may be the very man who on the witness stand would refuse to 

 testify to things that he doesn't feel sure of, and who, when he does 

 make a statement, may be implicitly believed. And the same remark 

 applies, in some measure, to nearly all the tests in Professor Miinster- 

 berg's questionary. If Professor Miinsterberg has laid himself open to 

 criticism in so many points, how much less would it be possible to 

 entrust to an ever}--day psychologist the decision of so delicate a ques- 

 tion as that of the degree of reliability of each of the witnesses in a 

 given case ? 



There is one very striking test, of a different character from any 

 of the others, to which I have made no reference, and which might be 

 pointed to as concrete proof of the correctness of the method in spite of 

 any criticism that may be brought against it in the abstract. This is 

 an experiment in which Professor Miinsterberg, having asked his class 

 to describe everything that he was going to do from one signal to 

 another, did certain conspicuous things with his right hand, upon 

 which he ostentatiously fixed his own attention, while at the same time 

 he did a number of other things with his left hand. The result was 

 that 18 out of 100 students were utterly unaware that he was doing 



